Refrigerator defrosting means



Jan. 4, 1955 LA FORTE 2,698,522

REFRIGERATOR DEFROSTING MEANS Filed Jan. 21, 1953 IA/l ENTOR: Lou/.5 1-.LAPoRTe;

ms Arr-a EN'EY United States Patent REFRIGERATOR DEFROSTING MEANS LouisF. La Porte, Rolla, M0., assignor to Francis L. La Porte, Burlingame,Calif.

Application January 21, 1953, Serial N 332,249

7 Claims. (Cl. 62117.55)

The present invention pertains generally to mechanical refrigeration,and more particularly to improved means adapted to defrost evaporators,or cooling units of refrigerator systems.

The primary object of this invention is to provide means whereby thedefrosting of evaporators, whether of the finned type, plate type, orbare pipe coil construction, can be accomplished rapidly andefliciently.

The subject matter of the present invention was originally disclosed inmy copending parent application, Serial Number 182,971, filed onSeptember 2, 1950, now Patent No. 2,641,908.

Broadly, that application discloses the incorporation in a conventionalrefrigeration system of a novel heat storage unit interposed between thecompressor and the evaporator, a liquid fiow retarding device enclosedwithin said unit, and a by-pass valve in the discharge line of thecompressor for diverting the gases passing through said line to theevaporator in a preheated condition during a defrosting operation.

The present invention is a continuation-in-part of the aforesaidapplication and the designated patent that matured therefrom, and isdirected particularly to the novel liquid flow retarding device thereindisclosed.

Broadly, said device includes a cylinder closed at both ends; an upperbaflie plate spaced inwardly from one end wall and extending downwardlyin the cylinder to a selected plane; and one or more lower bafile platesspaced inwardly from the other end wall and extending upwardly in thecylinder to a selected plane. The upper battle plate is imperforate;each lower baffle plate is provided with a small orifice formed in thelowermost region thereof.

The prime objective of the device is to sufiiciently restrict or retardthe flow of refrigerant deliverable thereto via a conduit at one end,and dischargeable therefrom via a conduit at the other end, so that whensubjected to heat, complete vaporization of the refrigerant is effected.

Because of the continuation-in-part status obtaining as above noted,only those views of the patent which are believed necessary for acomplete understanding of the instant invention have been reproduced inthe accompanying drawing, wherein Fig. 1 is a diagrammaticalillustration of a conventional refrigeration system incorporating thepresent invention:

Fig. 2 is a View in vertical section illustrating a heat storage unitincluding the fiow retarding device of the present invention;

Fig. 3 is a horizontal sectional view, on an enlarged scale, taken online 3-3 in Fig. 2, and particularly illustrating details of the liquidfiow retarding device enclosed within the said heat storage unit;

Fig. 4 is a vertical sectional view, on a further enlar ed scale.through said retarding device, the view being taken on line 44 in Fig.3;

Fig. 5 is a vertical sectional view taken longitudinally of the deviceon the line 55 of Fig. 4; and

Fig. 6 is a fragmentary view, similar to Fig. 2 wherein is illustratedan additional feature that may be included in the liouid fiow retardingdevice.

With particular reference now to Fig. l, the conventit 2,698,522Patented Jan. 4, 1955 compressor discharge line by numeral 28. Theliquid line leading from the receiver tank to the expansion valve isindicated by numeral 30. The usual shut-off valve is designated 32.

Usually as well known, the assembly including the evaporator, the drainpan, and the expansion valve is mounted in the space to be cooled,whereas the assembly including the compressor, the condenser, and thereceiver is located remotely therefrom.

While it is taken for granted that the operation of the conventionalsystem illustrated and thus far described is well understood, a briefsummary is not believed to be objectionably prolix at this point.

Thus, assuming that the temperature of the space to be cooled has risenabove a predetermined degree, any of the well known thermal responsivedevices will cause the compressor to start. As a result, refrigerant invapor form is withdrawn from the evaporator via line 26, compressed, isthereupon delivered to the condenser 12 still in vapor form, and thenceto receiver 14 in liquid form, via line 28.

Assuming that valve 32 is open, the refrigerant in liquid form ismetered or fed through the expansion valve 16 and into the evaporatorcoil 24. The ambient warmth or heat about the evaporator being absorbedby the refrigerant as is understood, the latter is vaporized, and inthat form returned to the compressor via suction line 26 to repeat thecycle until the temperature of the space to be cooled causes the thermalresponsive device to shut ofi the compressor, as is understood.

Durin tese c cles of normal compressor operation, the moisture pr valentin the ambient atmosphere settles upon and is gradually transformed intoa layer or layers of frost, which increasingly accumulate on theexternal portions of the evaporator. As is well understood, unless theselayers of frost are removed from time to time, the efficiency of anyrefrigeration system will eventually be reduced to a point where itsoperation is non-effective.

The present invention contemplates no change in the normal refrigerationsystem thus far considered. It does contemplate however, theincorporation in such system of novel means whereby the normallyemployed refrigerant or cooling agent may also serve, selectively, asthe defrosting agent, without requiring cessation of normal compressoroperations.

Referring again to Fig. l, numeral 34 indicates generally a heat storageunit, 36 a by-pass valve, 38 a vapor line, and 40 a loop portion formedin the latter. The up er end of the vapor line is in communication withthe inlet portion of the evaporator coil by means of a T fitting 42, asshown.

The incorporation of the non-conventional elements just enumerated will,when necessary or desired, cause the refrigeration system to supplypreheated gas vapors to the evaporator for defrosting the same in amanner to be explained later.

With particular reference now to Figs. 2 and 3, the heat storage unit 34includes a tank 44 containing a heat holding fluid, the upper level ofwhich is indicated at 46. Submerged in said fluid medium, and mounted inany suitable rnanner within container 44, is the liquid flow retardingdevice which embodies the concepts of the instant invention and which isgenerally indicated by numeral 48. Alsosubmergedand disposed beneathsaid device, is a loop or coil portion 5% formed in the suction line 26.Also submerged, and dis osed in said container below the sucti n coil59. is a coil 5'4 formed in compressor discharge line 2%.

The liquid flow retarding device 48. as will appear, is of primeimportance. As shown in the drawing it comprises cylinder closed at bothends, and interp sed in s=" tion line 26 between the coil 5% and that prtion of said line ertending from the tank 44 to the evaporator 18.

Tn horizon ally spaced relati n to the inlet nd wall 6 f cylinder 62. isan upper baffle plate 66 which extends downwardlv within the cvlinder toa plane sli htly bove the horiz ntal centerline of said cvlinder, asclearlv sho n particularly in Fi 5. it is noted however. that the desinated plane is not critical, and that the plate 66 may extend below saidcenterline if desired, as the broken lines su est.

In horizontally spaced relation to the outlet end wall 68 of cylinder62, is a lower baffle plate 70 which, as also seen to best advantage inFig. 5, extends upwardly within the cylinder to a plane slightly belowthe horizontal centerline of the cylinder. It is noted however, that thedesignated plane is not critical, and that the plate 70 may extend abovesaid centerline if desired, as the broken lines suggest.

Interposed between these two baffles, and in spaced relation thereto andto one another, is a plurality of lower baflie plates 72, two beingshown in the drawing. The intermediate bafiles are identical with thebaffle 70, and each of the lower baffies is provided with a smallorifice or bleeder 74, preferably formed therein adjacent the lowermostportion thereof.

As portrayed in Fig. 2, the delivery portion 76 of suction line 26enters the device 48 through wall 64, in a plane above the bottommarginal edge 78 'of nonperforate bafile 66. Near the outlet end of thedevice, portion 80 of said suction line depends from the lowermostregion of cylinder 62, and is in fluid communication therewith betweenend wall 68 and perforate bafile 70.

It is noted that by opening valve 36, the compressor discharge gases maybe directed into line 38. In normal refrigerating operation, said valveis closed so that the high pressure refrigerant discharged from thecompressor passes through the discharge coil portion 54 of line 28,thence on to condenser 12.

In this manner, most of the heat inherent in the compressed dischargedrefrigerant is absorbed by the fluid heat holding medium in tank 44.Thus, it should be manifest that during each compressor operation, heatextracted from the discharge line is stored, or accumulated, within thetank 44.

From coil 54, the thus partially liquefied refrigerant proceeds to thecondenser 12, thence to receiver 14, and thereafter, via cold liquidline 30 and metering valve 16, to the coil 24 as is understood, but onits return to the compressor via suction line 26, the refrigerant againtravels through the heat storage unit 34.

In other words, the refrigerant, in mingled vapor and liquid form,passing from the evaporator first enters the liquid flow retardingdevice 48, then travels through suction coil 50, whence it continues onto the compressor in completely vaporized form, as will now be explainedwith particular reference to Figs. 2 to 4. As previously noted, theliquid flow retarding device 48 is immersed within container 44 in theuppermost region thereof.

As the mingled vapor and liquid body of refrigerant is drawn into device48 through portion 76 of the suction conduit 26, it impinges upon thebafile 66. The vapors pass quickly beneath the bottom marginal edge 78of said bafile and onward into coil 50 as indicated by the Fig. 2 brokenline arrows, thence to compressor 10 in the usual manner.

The non-vaporized or liquid portion of the refrigerant however, iseither deflected downwardly from the baffle 66, or drops by gravity fromportion 76 of the suction line into compartment 82 definedlongitudinally of cylinder 62 by end wall 64, and right handintermediate lower baffle 72.

Bearing in mind that cylinder 62 is immersed in a body of heated fluid,a considerable quantity of this non-vaporized refrigerant is quicklytransformed into vapor form to rise and proceed onwardly via outlet 80and through coil 50 to the compressor. The residue simultaneously flowsinto compartment 84 via orifice 74 in the right hand baffle 72.

As the residue of non-vaporized refrigerant flows through compartment84, a considerable quantity thereof is quickly transformed into vaporform to rise and to also proceed onwardly to the compressor. Anyremaining non-vaporized refrigerant simultaneously passes intocompartment 86 via orifice 74 in the left hand intermediate baffle 72,thence to the outlet 89 via orifice 74 in bafile 70, and on tocompressor 10 in a now vaporized state.

From the foregoing, it should be evident that the device 48, providesfor the complete vaporization of the refrigerant en route to thecompressor from the evaporator. The orifices 74 prevent the flow of anyliquid slugs to the compressor, the orifice in the baffle 70 preferablybeing of a more minute diameter than the others, as illustrated in Fig.5.

Assuming now that the evaporator requires defrosting, valve 36 isopened, whereby gases from both the comtit) pressor and the condenserwill flow into line 38. Opening of valve 36, starts the defrostingcycle, which continues as long as said valve is open.

That is to say, the cycle continues uninterruptedly until defrosting iscomplete, whereupon closing of valve 36 will again place the system incondition to resume normal refrigeration operation.

The defrosting circuit is indicated by full line arrows in Fig. l, andwill be further described with reference also to Fig. 2. Aftermanipulation of valve 36 to open or defrost position, the high pressuregases from the compressor pass through the heat storage unit via line28, coil 54, valve 36, line 38, loop 40, T 42 and into the evaporatorcoil 24.

As the preheated gas circulates through the loop 40 and coil 24, it ispartially condensed. That is to say, the heat inherent in the vapors istransferred to the evaporator and the drain pan whereby to melt frostwhich had accumulated thereon. As a result, the refrigerant leaves thecoil 24 in a partially liquid state and proceeds viasuction line 26 tothe device 48 in the heat storage unit.

As previously explained in detail, passage of the refrigerant throughheat storage unit 34 completely reevaporates the same. Thus it leavessaid unit and proceeds via line 26 to the compressor in the form ofvapors, to repeat the cycle until the defrosting operation is brought toan end.

From the foregoing, it should be manifest that simple, highly efficientmeans for rapid defrosting operations without turning off the compressorare provided.

It should also be evident, that the incorporation in a conventionalrefrigerating system of the heat storage unit 34, and particularly theliquid flow retarding device 48, will increase the efficiency of thesystem in normal operation, and that said device plays a vital roleduring a defrosting operation also.

In other words and as hereinbefore explained, the novel bafllearrangement of the device 48 automatically, so to speak, impedes thepassage of the refrigerant through the cylinder 44 sufiiciently to allowfor the complete vaporization of said refrigerant as it proceeds fromthe inlet to the outlet end of said cylinder.

In the slightly modified embodiment of the invention illustrated in Fig.6, a vapor tube 88 is provided. The upper end of tube 88 extends throughan opening formed in the outlet wall 68 of cylinder 62 at a high level,and the lower end of said tube is connected into the suction line 26 asby a T fitting 90.

With this arrangement, some of the vapors will flow directly into saidvapor tube, whereas the remainder will flow into the suction line,whereby vapor fluidity will be facilitated.

From the foregoing it should be evident that the liquid flow retardingdevice of the instant invention includes novel means for attaining itsobjectives in a highly eflicient manner. It is to be understood that theprecise details of construction illustrated and described have beengiven in an exemplary rather than in a limiting sense, and that theinvention contemplates all modifications which may fall within the scopeof the appended claims.

What I claim is:

1. In combination with a refrigeration system of the character describedincluding a storage unit containing a heat holding fluid, a devicesubmerged in said fluid for retarding the flow of liquid refrigerant enroute from the evaporator to the compressor of said system, said deviceincluding: an elongated cylinder closed at both ends; means forintroducing said refrigerant at a high level into one end of thecylinder; one or more lower baffle plates for dividing the interior ofthe cylinder into a plurality of adjoining compartments; an upper bafiieplate for directing the introduced refrigerant downwardly into the firstone of said compartments; orifice means in the lowermost region of eachlower bafiie plate for establishing fluid communication between adjacentcompartments; and means for withdrawing the refrigerant at a low levelfrom the last one of said compartments.

2. The device set forth in claim 1 wherein the upper baffle plateextends downwardly in said cylinder to a plane in proximity to thelongitudinal centerline thereof, and wherein the lower bafile platesextend upwardly in said cylinder to a plane also in proximity to saidcenterline.

3. In combination with a refrigeration system of the character describedincluding a storage unit containing a heat holding fluid, a devicesubmerged in said fluid for retarding the flow of refrigerant en routefrom the evaporator to the compressor of said system comprising: acylinder closed at both ends; an upper baflle plate in spaced relationto one end of the cylinder extending downwardly therein to a selectedplane relative to the longitudinal centerline of the cylinder; at leastone lower batfle plate in spaced relation to the other end of thecylinder extending upwardly therein to a selected plane relative to saidcenterline whereby to divide said cylinder into a first and a secondcompartment; means for introducing said refrigerant into the cylinderbetween the upper plate and the adjacent end of the cylinder, saidrefrigerant striking against the bafile and being deflected downwardlyinto said first compartment; an orifice provided in the lowermost regionof the lower baflle plate for metering said refrigerant from the firstinto the second compartment; and means for withdrawing refrigerant fromsaid second compartment.

4. In combination with a refrigeration system of the character describedincluding a storage unit containing a heat holding fluid, a devicesubmerged in said fluid for retarding the flow of refrigerant en routefrom the evaporator to the compressor of said system comprising: a

cylinder closed at both ends; an upper batlle plate in spaced relationto one end of the cylinder extending downwardly therein to a selectedplane relative to the longitudinal centerline of the cylinder; a lowerbattle plate in spaced relation to the other end of the cylinderextending upwardly therein to a selected plane relative to saidcenterline; at least one intermediate baffle plate between said upperand lower plates extending upwardly in the cylinder to a selected planerelative to said centerline whereby to divide said cylinder intoadjoining first and second vaporizing compartments and a vaporcompartrnent adjoining said second compartment; means for introducingsaid refrigerant into the cylinder between the upper baflle plate andthe adjacent end of the cylinder, said refrigerant striking against saidplate and being deflected downwardly into said first compartment; anorifice provided in the lowermost region of the intermediate baflieplate for metering refrigerant from the first into the secondcompartment; an orifice provided in the lowermost region of said lowerbaffle plate for metering refrigerant from the second into the vaporcompartment; and means for withdrawing refrigerant from said vaporcompartment.

5. The device of claim 4 wherein the orifice in the lower baflle plateis of a more minute diameter than that of the orifice in theintermediate baflle plate.

6. In a refrigerant flow retarding device of the character described: anelongated horizontally disposed cylinder; :1 wall closing the inlet endof the cylinder; a wall closing the outlet end of the cylinder; an uppervertical baffle plate in spaced relation to the inlet end wall andextending downwardly in the cylinder to a plane in proximity to thehorizontal centerline thereof; an opening formed in said inlet end wallin a plane above the bottom marginal edge of the baffle plate to receiveone terminal portion of a first conduit, whereby refrigerant in mingledvapor and liquid form drawn into the cylinder via the conduit willimpinge against said bafile plate to deflect the liquid portion of therefrigerant downwardly in the cylinder; a lower vertical baffle plate inspaced relation to the outlet end wall and extending upwardly in saidcylinder to a plane in proximity to the horizontal centerline thereof; aplurality of similar lower baflle plates interposed between said upperand the first-named lower baffle plate in spaced relation thereto andrelatively to one another; an orifice formed in each of the lower baflleplates in the lowermost region thereof; and an opening to receive oneterminal portion of a second conduit, said opening being formed in thebottom portion of the cylinder between said outlet end wall and thefirst-named lower baflle plate aforesaid.

7. In a refrigerant flow retarding device of the character described: anelongated horizontally disposed cylinder; 21 wall closing the inlet endof said cylinder; a wall closing the outlet end of said cylinder; anopening to receive one terminal portion of a first conduit formed insaid inlet end wall in a plane above the horizontal centerline of thecylinder; an upper vertical baffle plate in spaced relation to the inletend wall and extending downwardly in the cylinder to a plane above thehorizontal centerline thereof; a lower vertical baflle plate in spacedrelation to the outlet end wall and extending upwardly in said cylinderto a plane in proximity to the horizontal centerline thereof; aplurality of similar lower baffle plates interposed between said upperand the first-named lower plate in spaced relation thereto and relativeto one another; an orifice formed in each of the lower baffle plates inthe lowermost region thereof; an opening to receive one terminal portionof a second conduit, said opening being formed in the bottom portion ofthe cylinder between said outlet end wall and the first-named lowerbaflie plate aforesaid; and an opening formed in said outlet end wallabove the horizontal centerline of the cylinder to receive one terminalportion of a third conduit the other terminal portion of which is influid communication with the second conduit aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS

